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Cellular and Molecular Biology

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AT-Rich DNA

CELLS-LYT3DD

Regions of DNA such as origins of replication and gene promoters are usually AT-rich, meaning that they have more A-T base-pairs than G-C base-pairs in their sequences.

What is the best explanation for this observation?

A

A-T base pairs interact more readily with DNA-binding proteins than G-C base pairs do.

B

More mutations to A or T occur than to G or C.

C

A-T base pairs have two hydrogen bonds while G-C base pairs have three.

D

DNA repair is biased toward A-T base pairs.